OBJECTIVE: The objective of this research project is to establish nucleotide sequence relationships of mammalian RNA tumor viruses so that viruses with unique sequences can be used as molecular probes to detect virus-related nucleic acid species in human neoplastic cells and perhaps human normal cells. APPROACH: Nucleic acid hybridization techniques are being used to measure the sequence relatedness of RNA genomes from representative members of three mammalian RNA tumor virus groups -- murine, simian, and feline. Once shared sequences have been found in human cancer cells with appropriate molecular probes, they will be characterized further in terms of examining melting profiles to determine how closely matched they are to those of viral nucleic acid species. In addition, base composition analyses and oligonucleotide fingerprinting tests will be done to chemically identify them.